Resinous coating composition comprising nitrocellulose and aldehyde modified amide polymer and metallic surface coated therewith



Patented June 14, 1960 RESIN OUS COATING CONIPOSITION CONIPRISIN GNITROCELLUL'OSE AND ALDEHYDE MODIFIED AMIDE POLYMER AND METALLIC SURFACECOATED THEREWITH.

Roger M. Christenson and Henry A. Vogel, Richland Township, AlleghenyCounty, Pa., asslgnors to Pittsburgh Plate Glass Company, AlleghenyCounty, Pa., a corporation of Pennsylvania No Drawing. Filed Feb. 25,1957, Ser. No. 641,871

11 Claims. (01. 260-15 This invention relates to useful resinousmaterials and it pertains more particularly to resinous materials whichare useful as film forming agents in coating compositions.

In a copending application, Serial Nmnber 584,473, filed May 14, 1956,now abandoned, which is a continuation-impart of Serial Number 490,409,filed February 24, 1955, now abandoned, it is disclosed that usefulresinous materials are readily obtained by reacting an aldehyde,particularly formaldehyde with an interpolymer of acrylamide and one ormore polymerizable ethylenically unsaturated monomers, particularlymonomers containing a C=CH group. The resulting resins range from softflexible materials to very hard, solids, depending upon the choice ofmonomers utilized in preparing the acrylamide interpolymer employed inthe reaction and upon other conditions involved in the reaction.

It has now been discovered that these resins are highly compatible withnitrocellulose, and when the latter is added in appropriate amount tomixtures of the resins in solvents, homogeneous solutions are formed.These solutions when spread as films and set or dried, provide surfacesof high gloss. Also the films obtained by use of the nitrocellulose inthe aldehyde modified acrylamide resin are characterized by a relativelyhigh degree of flexibility and good adherence to the substrate. Theseare characteristics adapting the material for many applications, as forexample in the finishing of sheet metal toys, furniture, or interiorpaneling or other articles of metal and the hke where high gloss andhigh mar resistance are desirable properties.

As previously indicated, the present invention has particular relationto the use of nitrocellulose to modify:

acr'ylamide resins and their interpolymers which have been reacted withan aldehyde and more particularly with formaldehyde.

The exact mechanism whereby the amide interpoly'- mers, constitutingcomponents of the materials of this invention are obtained is notdefinitely known but is believed to begin by the formation initially ofthe relatively. short chain soluble interpolymer, having approximatelythe following structure:

where M represents a unit of monomer polymerizable with acrylamide and nrepresents a whole number greater hyde as represented by formaldehyde toform N-methylol than 1. For example, if styrene is utilized as a secondmonomer, M would possess the structure:

Group M need not necessarily all be identical, since a" mixture of twoor more monomers may be reacted with the acrylamide to obtainmacromolecules and mixtures of macromolecules in which the symbol-Mrepresents a plurality of different groups. a

The short chain interpolymer is reacted with an aldegroups, thus to givethe structure:

the alkyl group being derived from the hydrocarbon portion of thealkanol utilized. The amount of etherification taking place depends inlarge measure upon the pH value of the reaction mixture, theetherification being favored by acidic reaction conditions.

Among the monomers which may be interpolymerized with acrylamide areincluded methyl acrylate, butyl acrylate, isobutyl acrylate, hexylacrylate, octyl acrylate, methyl methacrylate, ethyl methacrylate,'butyl methacrylate, styrene, vinyl toluene, dibutyl maleate, acrylicacid, methacrylic acid, maleic anhydride, vinyl ethers,

vinyl ketones, vinyl pyridine, allyl acetoacetate, glycidyl acrylate,methacrylamide, dimethyl benzyl methacrylate, vinyl esters and the like.-Mixtures of two or more ofv these monomers are included within thepurview of the invention. Some of the interpolymers for use informingthe coating compositions of this invention are three component,interpolymers of (1) acrylamide, (2) an alkyl acrylate in which thealkyl group contains from one to four carbon atoms and particularlyethyl acrylate, and

(3) styrene and vinyl toluene or'an 'alkyl ester ofmeth-j acrylic acidin which the alkyl group contains from 1 to 4. carbon atoms. andparticularly methyl methacrylate.-

By choice of monomers, it is possible to tailor the interpolymer to haveany desired degree of hardness or flexibility. It has also been foundthat a small quantity of an acid monomer, such as acrylic acid,methacrylic acid, crotonic acid, maleic acid, or -fumaric acid may beincorporated as an internal catalyst designed to impart to the coatingcompositions desirable fast curing'properties. In the preparation of thecoating compositions of this invention, the acrylamide component may ber ei 7 also beemployed.

itaconate .diamide, r t er plac d. by methacrvlantidef Other usefulcompositions polymerizable acrylamide.

have been based on major amounts of ethyl acrylate and minor amounts ofacrylamide; Such compositions may be regarded as resinous polymericplasticizers for nitrocellulose.

Interpolymers of acrylamide and added monomers which can be reacted withan aldehyde to form interpblymers: which. can be modified withnitrocellulose in.

'monomer or monomers are soluble at least at reaction temperatures. 7

Butanol has proven to be a; satisfactory solvent in most I cases.Isopropyl alcohol, butylCellosolve and mixtures of butanol orother-lower alka'nol with Water can also used a vanta eo s y solr nt t.SQ e-carem h erers ssdw en w t r s pr se t at t ystem, as. gummy olrm raiil dae m mers, the catalyst, the chammmdifying agent -iriany) in thesolvent and refluxing the resultant. solutionffor a 7 preeipitates' mayresult, especially athigher water levels 7 pr s neeot. lower. a cohols.o water. has een. foun mpe ature 1 31 135 or. hy a etateridr; the es r srentsagdhyd ocarhc s such-as ume a d. t e l k tmay In conducting thepolymerization reaction, a peroxygen type catalyst is ordinarilyutilized; Useful catalysts for this purpose include acetyl. benzoylsperoxide, hydroxy heptyl peroxide, methyl ethyl kefone peroxide,cyclohexanone peroxide, cyclohexyl' hydroperoxide, 2,4-di-(chloroben-zoyl)peroxi de-, cumene hydroperox-ide, t-butylhydroperoxide, rnethyl amyl ketoneperoxide, acetyl peroxide, laurylperoxide; benzoyl peroxide, methyl cyclo- 'hexyl ,hydroperoxide, pchlorobenzoyl peroxide, di-t-butylperoxide, per-acetic acid, t-butylpennal eic a-ci d, di t-hutyl ta'tbiaini; the, like.

Cunienehydroperoxideand henzoyl peroxide are presently among the moreeconomical of these and are in catfalyst systemsmay also be used aspolymerization catalystsin-the preparation of the acfylamideintergolY-mers. 1

r q antity of catalystiempl oyedfcan.bevariedcons d'erably dependentupon the spe edof reaction desired,

the activity of the catalyst andlof thfe monomer employed; wella otherfactors; Inrno'st instances,

. howevenis desirable to utilizeifron' t aboutjtll' percent '102.0fpercent'by weight based upon the interpol'yrneriz able mixture. ifhigh viscosities aredesired in the inter polymer" a low initial.leveljof catalyst fonowedb'y. the.

d'perphthalate, t-butyl perphthalicfl acid, t-butyl. pence--- tomodcratethespeed of reaction by; lowering: the reflux high catalyst levels, itis. often preferable to add to the reaction mixture controlled amountsof chain modifying materials. The mercaptans, such as dodecyl mercaptan,tertiary dodecyl meroaptan octyl mercaptan, hexyl mercaptan and the likeare conventionally employed for this purpose. However, still other chainmodifying agents, such as cyclopentadiene, allyl acetate, allylcarbamate, alpha-methyl styrene and its dimers, unsaturated fatty acidsor esters thereof and the like can also be added in controlled amountsto secure interpolymers of lowrnolecular weight; The elimination ofchain modifying agentshom: the interpolymerizable mixtures results finhigher viscosity interpolymers. which to iosses's'valil ahleip'ropertiesfrom standpoint. of fabrication. 1'.

Tljhe, polymerization .is preferably conducted by thoroughiyanmrapidty'agitatingfthe. acrylami'd'e, another iotheri 'mnnomer or. monotimesuflicientto obtain- .thedesired con er'sio'n.- -The polymerization willhev completed. :in -a..period of about ione'to sixteen hours.Aspreviauny indicated, it may in some instances, be desirable initiallyto add only a portion. of the catalysnl-the remainder being, added inincrements as. the; polymerization: progresses. External; cooling'of thepolymerization mixture to-robt-ain; controloffreflux conditionsis.ofteng-desirable: because of the.

rapidi rate ofire actiont andghecause. the, reaction. is quite'exothermic; Control. of the heatofreaction is alsoatv leashpartially:obtained; by: adding theacrylarnide to. the; polymerizatiommixtureincrementally. Y

1n;- the; polymers obtained by" the foregoing methods,

the. 'componentsz are-dis butedatrandomin the ohain. It willfbaapparentthatso-called block? or. fgratt techniques may: alsorbe. employed in:conducting thegpolymerizationv By blockorgraft methods, the components'may: be introduced into the composition in. regular se' quencezor;order,;-eachi segment being of. a certain. length. and periodicity.These. products can he madeso that the; acrylamid'e-portion is; in.fixed. position in.-the-. chain. This approach involves the preparation?of segments which reactxiir. groups; or: in sites. along the: preformedback-bone, from whichro'r to. whichr other.- segments: can be; growrnor;attached; By the'block or graft method, OIIBf'GKII'JPI'GPaI'E by choicematerials of different solvent andflaineresistance, adhesiomandisolvent,or watersolu-i bility; In: fact, almost any desiredproperty can. betailored? into the interpolymer.

' Interpolymers. prepared by the foregoing techniques,

. aszfoa: example by random polymerization. groupingsmr by block'xongraft: methodsnarer suitable for interaction.

9 with :formaldjeliyde: .or other: aldehyde in: order to. obtain resinswhich may be added..to, orreceivehdditionsof. nitrocellulosein.accordance. with theprovisions of this invention. 1.

. In conducting. the: reaction; with aldehyde, .formaldai? hydeimwatersolutionon in. a. lower; alcohol, suohaas 'j' f' a yia i ions' toobtain d sireo'cenversion ef the 1 rnrxture to an interpolymer ispreferably e'r'nployed. For 7 low"vis osity;iuterpolymfif rffllebulkof'thecatalystlis. added mitially and later additions areiincorporated.only re' thejdesired degreeofjconversiou, The incorof larger, amounts ofcatalyst into the, initial Lire u sin productspflower viscosity.

solve'd'fto obtain solutions of hi'ghjsolidshwntentnout of" relativelylow viscosity.,.Although the; molecular.

' weight can bereducedto somerextelntbytheuseof: a.

ialleariol ls'uch as but-a'nol, or annixtureofbutanol and'wate'r as areaction solvent coupled with the use of hutanol, may be employed.Likewise, formaldehyde? yielding: substances: such as paraformaldehyde,itn'oxymethylene or hexamethylenetetraamineimayrhetemployed:

and often are preferred: Itwill be appreciated thatstill othenaldehydesincluding: aceta'ldehydegibutyraldehyde' furfuraland others which.preferably contain only. atoms ofcarbon, hydrogen andtoxygen may beusedi 'Interpolymers suitable for reaction with he aldehyde componentcontain from about, 5 percent to about 45 percent by weightofacrylamide, the-:balance being other ethylenically unsaturatedniono'mere, It has been found that those interpolymers containing thehigher levels of acrylamide with'those monomers which ordinarily formhard homopolymers, when reacted with formaldehyde give hard,- andflexible. films, whereas interpolymers tcontaina ing; lower levelse ofiacrylamideswith; thOSfisIIlOD-OHIEIS: which ordinarily form softhomopolymers form. products that tend to be considerably softer. Ifmorethan one ethylenically unsaturated monomer is polymerized withacrylamide, the proportion of such additional monomers utilized willdepend upon the characteristics which such monomer or monomers willimpart to the final interpolymer and the degree in which suchcharacteristics are desired:

For example, in some ternary interpolymer systems, it may be desirableto utilize about 10-15 percent by weight of acrylamide and about 4045percent of each of 2 additional monomers, such as styrene, and ethylacrylate. In some instances, such as when acrylic acid or otherethylenically unsaturated acid is utilized as an internal catalyst, itis desirable that the interpolymer containv about 10-15 percent ofacrylamide, a total of about 75 percent to 88 percent of 2 additionalethylenically unsaturated monomers and about 1.0 percent to about 8.0percent of unsaturated acids. The amount of monomers necessary in anyinterpolymerization reaction suitable to tailor the product to meetspecific requirements can readily be determined by simple experiment.

In the reaction of an interpolymer with formaldehyde it is ordinarilypreferred to utilize two equivalents of formaldehyde for each amidegroup present in the interpolymer, although this amount may be inconsiderable excess of the amount necessary to form methylol groups onthe polymer chain. Accordingly, this ratio may be raised or lowered ifdesired. For example, the ratio may be as high as about 3 equivalents,or as low as about 0.2 equivalent of formaldehyde for each amide groupin the interpolymer.

The reaction preferably is conducted in the presence of a mild acidcatalyst such as maleic anhydride. Other acid catalysts such as oxalicacid, hydrochloric acid or sulfuric acid may also be used although thereis some possibility of gelation occurring if the catalyst is toostrongly acidic. Alkaline catalysts such as sodium hydroxide, potassiumhydroxide, hexamethylenetetraamine and other basic amines may also beutilized and in fact there is evidence to indicate that the use of thebasic catalyst tends to give faster curing resin films.

In the reaction of the aldehyde with the interpolymer, catalysts may bedispensed with entirely, but usually the reaction under such conditions,is less satisfactory than where a catalyst is employed.

The quantity of catalysts utilized may be varied widely; for example, aspointed out hereinbefore, if an alcohol solution of formaldehyde isemployed, the more acidic the reaction medium, the greater the amount ofetherification which will occur. If the aldehyde is used in the form ofan alcoholic solution, it is preferred to utilize from about 0.2 percentto 3.0 percent by weight of catalyst based upon the weight of acrylamideinterpolymer which is reacted with the aldehyde.

The reaction of the acrylamide interpolymer with the aldehyde can beconducted simply by adding the aldehyde and the catalyst (if catalyst isutilized) to the polymerization mixture obtained by polymerizingacrylamide and one or more ethylenically unsaturated monomers andrefluxing the resulting mixture for a period of about 3 to 5 hours oruntil desired viscosity is obtained.

The water of condensation can be removed by azeotropic distillation, asmay a portion of the solvent if so desired. In fact, when the aldehydeis utilized in the form of a solution in an alkanol such as butanol, itis often desirable that approximately half of the butanol be distilledoff at the end of the reaction period and be replaced by another solventsuch as xylol. It is preferred that the final resinous material have asolids content of about 20 percent to 75 percent by weight.

Similar polymeric materials may also be obtained by first reacting theacrylamide with an aldehyde such as formaldehyde to form an alkylolacrylamide, for example methylol acrylamide, and then polymerizing theproduct with one or more of the ethylenically unsaturated mono: mericmaterials disclosed hereinbefore. The polymerization utilizing methylolacrylamide is carried out substantially in the same manner as whenacrylamide is interpolymerized with one or more monomers.

Regardless of the method by which the resinous material is obtained, theproducts are characterized by the presence of recurring groups of thestructure:

wherein R is a lower aliphatic hydrocarbon radical, that is the radicalderived by removing oxygen from a loweraliphatic aldehyde; for example,if formaldehyde is used, the radical R represents a methylene group {CHWhen an alcoholic solution of the aldehyde, for example, a butanolsolution of formaldehyde is employed, etherification may take place andat least a portion of the alcohol is so reacted into the polymer chainthat at least some of the radicals R will be represented by a loweralkyl radical such as butyl while any that are not alkyl are hydrogen.

When the aldehyde is used alone, that is in the absence of an alcohol,the radical R of course, will represent hydrogen. The free valences maybe satisfied with either hydrogen or hydrocarbon depending upon theamide which is utilized.

The following examples are illustrative of the preparation of anacrylamide interpolymer and the subsequent reaction of the same withformaldehyde to providea resin which is compatible with nitrocelluloseover a wide range of proportions:

Example A In this example, an interpolymerizable mixture was preparedcomprising:

Acrylamide -pounds 3 Styrene do 5 Ethyl acrylate do 12 Butanol do 20t-Dodecyl mercaptan grams 90.8 Cumene hydroperoxide do 90.8

This mixture was placed in a reaction vessel under a reflux condenser.The mixture was refluxed for 2 hours after which 45.4 grams of cumenehydroperoxide was added and refluxing was continued for an additional 2hours after which an additional 45.4 grams of cumene hydroperoxide wasadded and the mixture was refluxed for a final 2 hour period.

The resultant product was an interpolymer solution which was adapted forreaction with formaldehyde or. a substance yielding'formaldehyde. Inthis particular example, a solution of formaldehyde in normal butylalcohol, known as butyl Formcel was employed. This was understood tocomprise 40 percent formaldehyde and 51.5 percent butyl alcohol, therest being water.

The reaction mixture comprised:

In'terpol'ymer solution (as above described) The foregoing. Formaldehydesolution 6.34 pounds. Maleic anhydride 36.3 grams.

The ratio of formaldehyde to the acrylamicle component of the resin wasapproximately two moles of the former to one mole of the latter.

The resultant mixture was refluxed for 3 hours. During this time, waterwas decanted from the condensate.

Subsequently, the mixture was azeotropically refluxed for 2 more hours.The product obtained was of a solids content of 51 percent and of aviscosity of X upon the Gardner-Holdt scale. The resin was termedresinA.

7 7 This preduet was higlilycompatiblewith nitrocellulose.

mixtures of'nitrocellulose an'dthe resin could be em pldyedffor',asset-1 wood, metal, stone or the like, for example interior or'exteriorapplications This mixture was placed in a reaction vessel. under areflux condenser andwas refluxed for -4 hoursto'pr'ovide an interpolymerwhich wassuitableior further reaction with formaldehyde to providearesin adapted'for modification with nitrocellulose in accordance withthe provisions of the present invention. To this end, there was added6.34 pounds of a solution. of formaldehyde in butanol and being of thecomposition described in Examie A and 36.3 grams of maleic anhydride;The mixture was refluxed for 3hours, after which, it was azeotropicallyrefluxedpfor an additional 2 hours' The resultant product was'of highcompatibility with nitrocellulose and compositions of the same with thelatter material were useful for coating Wood, steel and similarmaterials; The product was of a solids content of 49.3 percent by weightsTYREriiesoriYmMmir C'QPOLYll/I'ER 7 The foregoing mixtures werepigmented "with rutile titaniumdioxide ins ratio of 24 pounds per 100poundsof'vehicle. u 7 V Solvents were also 'inetud gl in order" (itmentors-dis- The solution may befapplied with or without pigment-a apers n a to prvid 's y'abl 1 The tieii as may be required. Themixturesof the-resin, and position or the solvent system was as follows?nitrocellulose may he applied to primed orunprimed sur- 1 I Inaccordance with this example, an interpolymer was Methyl ethyl ketone' a1.0 prepared from acrylamide, methyl methacrylate and ethyl Denaturedalcohols;s eea- I 5.3 acrylate. The charge comprised: Toluol 'i l ".Q-

Acetone 1 fiitlif fiithasag:jijjijjjjjjjjjjjifllf:: in w k e l: t yadmire V 12 Acetate of monoethyl ether ofethylene glycoLl-sfl- 12. 25:T?-"f"* g Solvents were added until a total solids content was about c has 35 percent by weight. The nitrocellulose was highly meme rye operoxl6 :0 compatible with the mixtures. The compositions were applied tosheet steel test panels one set of which were bare or unprimed. Thepanels'ofthe second set were primed with a primer such as isconventionally employed under nitrocellulose lacquers namelxonecomprising an alkyd resin or an alkyd resin modified by means oftComposltloninGrams Sward 'Bump; B's'r'1d" (Bare) Siifzird Bend sureN.O.-Resin-DOP (Bare) (Bare) (Primed) (Primed) V (Primed) maiiths, V 7os's' 35" 50 32 28" 6 very good 90' I0 5 4 0 '36 en-d0 90 25 62. 6 l2. 528 ,9 20 60 20 14 27 18 25 15 72.5 12.5 18 27 20' 26 10 80 10 16 31- 16' 27, 20 25 10 27' 12 2 6,

NorE;-N.O.=nitr0cellu10se. no' drseytipiitfiaiste Gloss-by Gardnerglossmeterg and of a viscosity ofY to Z on the Gardner-floldt s'calejThe resin was termed resin B.

The following examples illustrate the preparation of pigmentedblends'o'f (a) the resins of Examples A and B and (b) nitrocellulose. Inthe examples, I and II, a

series of blends which differed from each other in the nitrocellulosecontent were prepared:

2 Example I The resin was the same: asithat of Example A. The

' compositions of the vehicles of'the'series in percentages by weightwere" as follows:

tReslnA .Dluctyl-f Nitrocellulose l phthalate 10; 8550 7 ill: 10. 70.020.

, 25. 7 62 5 1 2. 7 20 ft) 20. '20; 5510 25. 35. t 59.0 15.

l The; nitrocellulose was; secondphut couldbe replacerlbyultrarelllflose ofotherViscosity: N a

ooobioo oo,

It will be observed that many (tithe-films" "xhihited T t Example 11 YThe resinzin this: example was B of Example];

resin was -substituted 'for resin 'A' 1 1111116 several tests"; of

Example I The solvent system was substantiall'y the same as i'n ExampleI; thenitrocellulose was quite-'com patible' i'n-the mixtures Themixtureswere usedite spray' coat steel .panels,the'- films when curedwere of ge -e gloss,;-good hard1ress; good adhesion afidgoodlfl'e ility.

The I memes with respect to the tests of asimple'r'f These materialsapply with respect to mis s-sample;

con" ld ee empleyed as an 'anteinotiv seqner, seen dustrial finishes, tocoat sheet steel furniture, paneling and the like. The results aretabulated as follows:

to efiect cross-linking. The resultant resin at a concentration of 46.5percent by weight in butanol had'a vis- METHYL METHACRYLATE-AORYLAMIDEOOPOLYMER Composition, Grams v Fla. Expo- Sward Bump Bend (Bare) SwardBump Bend sure4 (Bare) (Bare) (Primed) (Primed) (Primed) months, No.Resin DO? 7 Gloss as 60 15 as 9 26 so 20 55 25 1s 25 14 2s 20 so 20 1826 16 25 25 70 s 40 a4 e 25 62 12.5 28 2e 28 .-do s5 75 12.6 18 27 18 28Excellent... 10 so 10 1o 28 16 2s .do 10 7o 8 2s 10 so .do

Example III cosity of about H on the Gardner-Holdt scale, the resintermed resin C In some instances, it may bedesirable to incorporate wasa Small amount of an acid imatbe blend of the resins 20 Apigmented pasteof this resin was made up as follows. A, B, C or D whereby to increasethe rateof cure, the Grams adhesion. to metals or other desirableproperties of the Titanium dioxide 496 material. The following testsillustrate the addition of Phthalocyanine (tint) 4 such acid components.In each instance, the resin was Resin solution (46.5% solids) 280 resinB of Example B; the nitrocellulose was /2 second A Solution ofnitrocellulose was also made up material; dioctyl phthalate was employedas a plasticizer. prising, The composition comprised:

P r en by weight Nitrocellulose /2 second) 273 Nitrocellulose 25.0 E yla c hol 65 Resin (per Example B) 62.5 Blltyl I 91 Dioctyl phthalate 12,5I PI PYI acetate 180 I a Toluene 155 To this mixture was added 0.5percent by Weight of phos- PhD-tic acid pigment and sclvent as inEXamPle I to The paste and the nitrocellulose solution were thenfurprovide coating composition of percent total solids. 35 that i' addedresm sollltlon to f a Sena? This was sprayed upon sheet steel panels.The fi of coating materials of the fOllOWlIlg composition: when cured at175 F.-250 F. for about 30 minutes, had good adhesion, good flexibilityand good gloss. Final Vehicle The results of the tests are tabulated asfollows: p $5355" giifi gfig 4,0 Grams (solution) grams 7 grams PercentResin; Unprlmed lrlmed 3 db an g 1 78.2 90.0 230.0 20 so hflmiimi ist.-.26-. 23. 0 33-3 gg-g gg-g 3g 53 Ben 'i' E s D 7812 Q2250 13310 soThipalms were of high 8 9 and W The nitrocellulose and resin werecompatible in t0 P01513116 72 hours wlthout bllstelmg- The the solution.Panels of steel were-coated with the tenal could be used to c oatarticles of sheet steel. tunes o bt i fil whi h hen cured at 180 F. for30 The followmg addmonal Samples of slmllar sohds 50 minutes adhered tothe metal and were hard but flexible.

composition and solvent content but characterized bythe use of 0.1percent by weight of the mixture of difierent acid components wereprepared, applied to steel test panels and tested:

The mixture was refluxed, for example as in Example A with a peroxygencatalyst to form a liquid interpolymer. The interpolymer was thenfurther refluxed with formaldehyde in butanol in a ratio of about 2moles formaldehyde per mole of acrylamide as in Example A,

The Sward hardnesses of the various mixtures were 22 for- C and 26 forD. The D composition was exposed against commercial automotive lacquerbased on nitrocellulose and conventional plasticizer. After 4 months inFlorida the experimental material had a gloss of compared to 70 for theconventional lacquer. The improvement in favor of the new material wassubstantial.

Example V The acrylamide resin of this example comprised:

Percent by weight Acrylamide l0 Ethyl acrylate butanol, had a viscosityof O on the Gardner-Holdt scale.

The resin was pigmented as follows:

Grams Titanium dioxide 496 Phthalocyanine (tint) 4 Resin solution 275The pigmented paste was then incorpforated with added resinzs'olutionandnitrocellulosesolution to provide :the following coating compositions:

a saopas 4. The resinous composition of claim .1 wherein theinterpolymer :isa acopolymer of styrene :and acrylamide.

5. The resinous composition of claim 1 wherein the yinterpolymerisaninterpolymer of styrene, ethyl acrylate,

These compositions weregusetul to'coat jsteehiron andjjjjj the like.They could be applied tosteel furniture, auto- Q mobiles and variousitems. to decorate the samefljl'he Sward 'hardnesses were 8 for A, forQB, 20 .for C and 18 for D. When the D composition was exposed inFlorida;f0r 4 months its gloss was 90 compared to 70 fora commercialautomotive lacquer based on nitrocellulose and a conventionalplasticizer. It was substantially better than the latter as to gloss.

' Theinvention contemplates the addition of various compatibleplasticizers to the mixture :of the resins and the nitrocellulose ofytheexamples; .These'plasticizers comprise -phthalate esters quitegenerally, epoxidized oils such as epoxidized .soya oil, alkyd resinswhich are plasticizers, epoxy resins which are, plasticizers, andothers.

The blends of the resins of the examples and nitrocellulose may also befurther blended with other resins and plastics'suc'h as epoxyre'sin'sj'melarnine resins, urea resins, alkyd resins, phenolic resinsand" the like' We'claim: 7 '1. A' resinous "composition comprising able11d of nitrocellulose andan interpolymer of an amide selected from thegroup consisting of acrylamide, methacrylamide and itaconic 'diamide;and at least one -other monomer containing a' C=CH group, said'interpoly'mer containing from about 5 to percent by weight of saidamide in polymerized -form 'based on thetotal weight of saidinterpolym'er and being characterized by having at least sisting ofhydrogen, ruryrsnr lowenalkyland' R1 isa 40 'one hydrogen atom 'of anamide nitrogen replacedby i g the structure i i memberselected 'from'thegroup consisting of hydrogen, 7

lower alkyl and butoxye thyh'said nitrocellulose and said interpolymerbeing present-in the relative percentages by weight of from 10 topercentnitrocellulose and to 50 percent of said interpolymer. v t

2., The resinous composition of claim 1 wherein the nitrocellulose is of:the viscosity of approximately /2 second;

3. The resinous composition ofjclai m 1 wherein the interpolymer is an'interpolymer ofstyrene, ethyl acrylate and'acrylamide; e e

, coating thereon a 'film of claim 1.

acrylamide, and an unsaturated carboxylio acid.

6. An article having a metallic surface having as a the resinouscomposition of 7. The resinous composition of claim l wherein the Istructure 7 n 1 action,-

and R are each hydrogen atoms. 9..The resinous composition of claim 7,wherein and R are each hydrogen atoms.

cellulose and an interpolymer of acrylamide and .at least one other'monomer'having 'a C=CH group, said interpolymer containingfrom aboutSwto 4-5 percent'iby weight of said acrylamide in polymerized form:based on the .total weight of the interpolymer and being characterizedby having *at' lea st one hydrogen :atom of an amide nitrogen replacedby the structure .,-CH OH and said :nitrocellulose and said interpolymerbeing present in the relative percentages byflweight .ofirom 10 to. 50percent nitrocellulose, 10.780. to 501percent :of said interpolymer. w

11 A resinous composition comprising a. blend of nitrocellulose and an'interpolymer of acrylamide and 'at least one other monomer .havinga C=CH, group, said interpolymer containing from about 5 .to '45 percent byweight of said acrylamide in' polymerized form based on the total weightof the ,interpolymer and being characterized by having at least onehydrogen atom of fan amidonitrogen replaced by th -gm e .l a CHie .o c.cH;eH,eH,"

50 percent-nitrocelluloseto BO to SQ percentof said in 7 ReferencesCited in the' file ofithislpitent UNITED sTArnsfP TE rs '1 Reid 'Jan.1s,1935 7 OTHER REFERENCES" Schildkn'echt: Vinyl and Related Polymers, pub:lished' by JohnWiley and Sons, New York, 1952, page 32l.j 7 t v10.:A'resinous compositioncomprising a blend of niti'o-

1. A RESINOUS COMPOSITION COMPRISING A BLEND OF NITROCELLULOSE AND ANINTERPOLYMER OF AN AMIDE SELECTED FROM THE GROUP CONSISTING OFACRYLAMIDE, METHACRYLAMIDE AND ITACONIC DIAMIDE, AND AT LEAST ONE OTHERMONOMER CONTAINING A >C=CH2 GROUP, SAID INTERPOLYMER CONTAINING FROMABOUT 5 TO 45 PERCENT BY WEIGHT OF SAID AMIDE IN POLYMERIZED FORM BASEDON THE TOTAL WEIGHT OF SAID INTERPOLYMER AND BEING CHARACTERIZED BYHAVING AT LEAST ONE HYDROGEN ATOM OF AN AMIDO NITROGEN REPLACED BY THESTRUCTURE